Bar code symbols have become widely used in many industries, such as, for example, grocery and food processing, retail department stores, industrial inventory tracking, document control and many other data control applications. Various bar code readers utilizing several illumination sources have been developed to scan and decode symbol patterns and generate multiple digit representations to be used typically as inputs to computers for automatic processing. Bar codes comprise a very error-free method of manually entering data into a computer.
Bar code readers have generally been classified into two categories. The first category is a lightweight portable hand-held scanner which can be supported in the hand of a user. The user positions the hand-held scanner within a predetermined distance from the object bearing the bar code, manually actuates the scanner to initiate reading and then moves the scanner to additional objects. The second category of bar code scanners are those which are stationary or built into an immovable structure such as a supermarket counter. These scanners are referred to as point-of-sale or tabletop scanners and may utilize a moving beam or fixed beam. Objects bearing the bar code are oriented by the user and are moved through the system for reading of the bar code.
Both the portable hand-held scanners and the stationary scanners have inherent deficiencies. The hand-held portable scanner, although being lightweight, is not always convenient to use in assembly-line applications where the user is processing coded objects over extended periods of time and where it is necessary to use both hands of the user to manipulate the objects. In some applications, the handheld scanners are difficult to manipulate while simultaneously moving the objects or performing other tasks at a point-of-sale terminal. Stationary scanners, on the other hand, allow the operator's use of both hands for manipulating objects bearing the bar code to be read which may increase the operator's efficiency in scanning objects. However, stationary bar code scanners are generally heavy, large in size or inconvenient to be brought into scanning installations.
A need has thus arisen for a bar code scanning system that incorporates the advantages of both a hand-held scanner as well as a stationary or fixed scanner which can be used in either of these modes of operation. With such a system, the reading of printed bar code information for automatic data entry can be accomplished by using a hand-held scanner to read the data by moving the scanner to the object or alternatively bringing the object to the scanner in its fixed mode of operation. Such a scanning system eliminates the need for two types of scanning systems at a single work station and minimizes the deficiencies of either a single hand-held portable scanning unit and a fixed scanning unit.